Marti Noxon was a producer of Buffy the Vampire Slayer, and now she's coming back to superpowered teenagers with the movie I Am Number Four, coming next month. She talked to us about aliens, super-violence, and dealing with internet haters.

If you're a fan of Buffy the Vampire Slayer, then you're also a fan of Marti Noxon, whose creative vision helped shape the show. She wrote more episodes of Buffy than anyone apart from Jane Espenson and creator Joss Whedon, and became the show's executive producer. And now she's the screenwriter of I Am Number Four, the movie based on the bestselling young adult novel about a fugitive alien in high school. Number Four has to discover his superpowers and romance a formerly popular girl named Sarah, while dealing with both mean jocks and the super-alien predators who are hunting him down.

We were lucky enough to talk to her about I Am Number Four — and we'll also have an exclusive follow-up Q&A with her about her other movie project, Fright Night, later on.

Minor spoilers for I Am Number Four ahead...

What appealed to you about adapting this novel?

Well, when I came into the project, there were already a couple of scripts, and so at that point, I was reacting more to the the movie that Dreamworks was envisioning. And I think I responded to the same thing that I love about the Spider-man stories, which is real characters in extraordinary situations, and to some extent the Buffy story too. Even though the main charater knows that he's from another planet, we're on a journey with him, as he discovers his power and the challenges that he's going to face. And the whole goal was to keep it grounded.

So there were already two scripts that other writers had done? What did you bring to it, when you came in and rewrote it?

I did a lot of work on some of the character stuff. There was a really good structure in place, and a lot of good character foundation. But part of what Dreamworks was looking to do was expand the appeal of the movie, and make sure that the female characters were feeling really lived in. And Sarah and John's relationship is really a big part of the movie. I was just like, "Teen alien romance? I'm so in." Supernatural mixed with romance is one of my sweet spots. I'm a sucker.

Reading the novel, I didn't really understand Sarah's character that much. She's the popular girl, but she's given up being popular and now she's sort of an outcast.

I hope that in the movie, it's much more clear, what happened and why she is where she is in her life, and why she sees things the way she does. And of course, the actress, Dianna [Agron] from Glee is amazing. She's so appealing, so warm. She gives it a whole additional dimension, which is really exciting to see.

What's it like going back to paranormal high school after Buffy? How is this different from how Buffy treated these themes?

I mean, tonally this is a really different movie. This is much more in the vein of Twilight. The world of Buffy was overtly comic, overtly kind of pushed into a kind of genre world that was a little bit over the top. This is much more living in that space of "What if this was really happening?" And so, tonally, that's just a different vibe, you're not looking as broadly at the comedy, [and] what there is much specific to the charcters. The dialogue on Buffy was just so stylized. I went back and rewatched a couple of episodes, and I was like, "Wow, I forgot how intensely we worked the language." They were speaking their own fricken language. That's a really fun kind of writing, but it's really different than trying, on some level, to keep your ears to how people are talking now and what sounds credible.

So there's been a huge surge in interest in young-adult paranormal and science fiction stories, including things like Hunger Games as well as Twilight. What do you think is behind this?

I don't know. I don't know if it's cyclical. I don't know if the big shows like Buffy and Roswell and Supernatural and [other] shows on television penetrated that market, [and] it's kind of feeding on itself. Now there's more books like that, and more media like that. There were a few shows that broke through and captured people's imagination. And the interesting thing is, I'm always talking to real young people who are discovering Buffy, Angel and Firefly right now, through DVDs. And of course, the Twilight phenomenon was a huge, huge boon to that industry. I do think it's an appetite that's been discovered over the last 10-12 years, and we'll see if it cycles out again.

I'm not a huge apocalyptic theorist. You know, a lot of people have theories about people's fear of the end of the world, and that really makes us way into fantasy. And tough times lead to this kind of renaissance in fantasy fiction. I just think it comes and goes into popularity. Lucky for me, we're in a big upswing.

I heard revisions to the novel went hand in hand with scripting the movie version. How did that process work?

There was definite communication between James [Frey] and the studio. And by the time I came on, the book was already in galleys, so we, again, were locked into things that were written. But I know that earlier in the process, yeah, there was a little bit of give and take about things that the studio would tell James we were doing, and he might cotton to some of those ideas.

What were the biggest differences you ended up with between the book and the movie?

[The movie is] very much in the time and space it's in. We don't do a lot of backstory on [the alien's home planet] Lorien. And we don't do a lot of explaining of the mythology of the nine. That's kept relatively sparse. But I think it's pretty easy to understand the general concept. They came here, the Mogadorians are after them, and the nine [aliens] have been depleted. All that's pretty clear. But we found that too much mythology was confusing people. It's all backstory, it's all stuff you don't actually see.

One of the interesting things in the book is that it's a science fiction world, with aliens and space travel, but there are also spells and magic. How do you work that in the movie?

I think if there's one element we didn't incorporate much from the book, [it would be the magic spells]. We didn't do a lot about the magic or the spells, there are allusions to it, we didn't go too much into that. And I think if there's more I Am Number Four, there'll be more of that.

Back when you were working on Buffy, you were one of the first creative people working in Hollywood to experience an internet backlash. Nowadays it's common for writers and producers to be attacked on message boards, blogs or other online forums, but it was a relatively new phenomenon when you experienced it. What did you learn from that experience?

I was personally attacked for [Buffy] season six, yeah. [Laughs] I mean, on the one hand, I get that people didn't really understand the process, because Joss was very involved creatively [in that season]. So it was like okay, people don't really know what's going on here, that's fine. But on the other hand, I am hypersensitive, and criticism wounds me far too deeply. And I never cultivated a fanbase on the internet, in part because I'm afraid of needing that, needing the approval of people I don't know. I already worked so hard to get it from the people I do know, [so] a legion of people who are strangers to me is even more daunting. So I felt like I could have gone on there, and defended myself and explained myself. But then I thought, "You know, if I get into this, it's a rabbit hole, from which I shall never return." [Laughs]

It was uncomfortable, but ... it also probably did me a real service, because I mostly steer clear of all that chatter, I don't go on the Web to look at comments about I Am Number Four. I haven't looked at comments about Fright Night. I just keep my head down and do my work. And you know, I probably missed some good and thoughtful stuff, but in the big picture, it can be a real creative drain. It can be a distraction. I know that people on genre shows have jumped off Twitter or [other online forums]. Because they get into defending themselves. There's a benefit to dialogue with your audience, but so many people in the internet are ready to engage in a fight. And that's just not my style.